On Friday 09 October 2015 18:15:40 Bjorn Helgaas wrote:
>
> I don't know if this should be a kernel taint, a simple warning in
> dmesg, or what. I guess the tainting mechanism is probably too
> general-purpose for this, and add_taint() doesn't give any dmesg
> indication. We wouldn't see the taint unless the problem actually
> caused an oops or panic. In this case, I think I want a clue in dmesg
> so we have a chance of seeing it even if there is no oops. So
> probably something like a dev_warn("non-compliant config accesses")
> would work.
>
> You really should double-check with the hardware guys, because it's
> pretty obvious that the PCI spec requires 1- and 2-byte config
> accesses to work correctly. For example, if you read/modify/write to
> update PCI_COMMAND, you will inadvertently clear the RW1C bits in
> PCI_STATUS.
Would it help to require a DT property here that flags the device
as having a broken config space?
Then we could implement both in the driver, and only use the
RMW based implementation if the firmware describes the device
as "altera,broken-pci-config-space".
Arnd
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